On Xbox One, Xbox Live Gold members can download Defense Grid 2 for free during the month of May. Costume Quest 2 will be available as a free download from May 16th to June 15th.
On Xbox 360, starting Sunday, 01 May, GRID 2 will be free for Xbox Live Gold members through May 15th. Then on May 16th, Xbox Live Gold Members can download Peggle for free through May 31st.
SOURCE : MAJOR NELSON